To fill a fuel reservoir with fuel, a fuel pump nozzle is inserted into a filler pipe opening into the fuel reservoir, thereupon allowing fuel to be introduced into the fuel reservoir. To enable the fuel reservoir to be filled unhindered, the air in the fuel reservoir or the air/gas mixture in the fuel reservoir must be able to escape from the fuel tank since, otherwise, a pressure rise within the fuel tank would hinder the filling process.
To vent air from the fuel reservoir, one or more venting valves in fluid communication with a vent line are provided in the fuel reservoir, wherein the vent line is in turn in fluid communication with an activated carbon filter or a filler pipe head. Air/gas mixture displaced from the fuel reservoir is filtered by the activated carbon filter, ensuring that only small quantities of hydrocarbons, if any, are released to the environment.
Venting and/or air admission valves known from the prior art, which are also referred to below simply as venting valves or shutoff valves, comprise a hollow valve housing, which has at least one ventilation opening, by means of which a valve housing interior is in fluid communication with the environment thereof. When the venting valve is installed in a fuel reservoir, the valve housing interior is in fluid communication via the ventilation opening with the fuel reservoir interior, thus allowing an exchange of fuel vapour/air mixture between the fuel reservoir interior and the valve housing interior via the ventilation opening. The valve housing interior is in fluid communication with a vent line via a vent opening arranged in a valve seat. A valve body, which can move freely in the valve housing interior and is also referred to as a float, float element or buoyant element, closes the vent opening at and above a predetermined fuel level within the fuel reservoir, thus preventing gas escaping from the valve housing. Below the predetermined operating fluid level, the valve body is at a distance from the vent opening, with the result that the valve housing interior and the vent line are in fluid communication.
The distance between the operating fluid level and the fuel reservoir inner wall on which the venting valve is fastened at which the valve body is subject to so much lift by the fuel that it closes the vent opening is referred to as the shutoff height.
When the operating fluid level has reached the shutoff height, the valve body is subject to such lift from the operating fluid that the valve body closes the vent opening in the valve housing. If more fuel is introduced, the pressure within the operating fluid reservoir rises, with the result that the operating fluid level in the filler pipe rises and the filling process can be ended automatically at a given fluid level within the filler pipe.
In the case of operating fluid reservoirs known from the prior art, the venting and/or air admission valves are introduced into the operating fluid reservoir through an opening in an upper shell. The valve housing is then connected to the upper shell by a weld, an adhesive bond or in some other way. In order to produce a corresponding operating fluid reservoir, it is consequently always necessary to produce an opening in the upper shell and then to connect the valve housing to the upper shell in an additional method step. It is furthermore necessary to attend to the leak tightness of the connection between the valve housing and the upper shell of the tank.
To achieve different shutoff heights, it is consequently furthermore necessary to use and therefore also store different shutoff valves.
EP 1 213 173 A2 describes a system for recovering fuel vapors from a motor vehicle tank comprising a tubular body fastened in the interior from the fuel tank, wherein the tubular body is formed integrally with a fuel tank wall. An interior of the tubular body is in fluid communication with a service duct via an opening wherein the opening is embodied as a through opening through the fuel tank wall. The system furthermore comprises a float arranged inside the tubular body. In the installed position of the fuel tank the float is at a distance from the vent opening when a fuel level within the fuel tank is below a shutoff level, with the result that the float is in an open position and the interior of the tubular body and the service duct are in fluid communication. In the installed position of the fuel tank the float is subject to a lift from the fuel in the interior of the tubular body such that the float is in a closed position and closes the vent opening when a fuel level within the fuel tank is above the shutoff level, with the result that the interior of the tubular body and the service duct are not in a fluid communication via the vent opening.
US 2010/0065134 A1 describes a fuel shutoff valve including a valve chamber, a casing, a float, and a shock absorber. The casing includes a body, a cylinder and a seal. The float is accommodated in the valve chamber. The shock absorber includes a seat attaching to and detaching from the seal of the casing. The shock absorber is connected with the casing via a locker inserted in a guide hole of the casing in that way, that the distance of the shock absorber to the seal of the casing is variable.
DE 10 2010 004 778 A1 describes an oil exit valve for controlling the fluid stream of oil through an opening of a crankcase ventilation arrangement. The valve is realized as a separate member which is not integrally formed with the crankcase ventilation arrangement. The valve comprises a valve plate provided with latching elements which can be passed through an opening of the valve housing.
US 2004/0231720 A1 describes a check valve especially for water cooler assemblies operative at a liquid and gas interface that closes to prevent a substantial flow of liquid beyond the valve but returns to a normally open position upon experiencing a slight vacuum from the liquid originating region.